Plant Immune Responses to Parasitic Nematodes.

Kazuki Sato,Ken Shirasu,Yasuhiro Kadota

doi:10.3389/fpls.2019.01165

Abstract

Plant-parasitic nematodes (PPNs), such as root-knot nematodes (RKNs) and cyst nematodes (CNs), are among the most devastating pests in agriculture. RKNs and CNs induce redifferentiation of root cells into feeding cells, which provide water and nutrients to these nematodes. Plants trigger immune responses to PPN infection by recognizing PPN invasion through several different but complementary systems. Plants recognize pathogen-associated molecular patterns (PAMPs) sderived from PPNs by cell surface–localized pattern recognition receptors (PRRs), leading to pattern-triggered immunity (PTI). Plants can also recognize tissue and cellular damage caused by invasion or migration of PPNs through PRR-based recognition of damage-associated molecular patterns (DAMPs). Resistant plants have the added ability to recognize PPN effectors via intracellular nucleotide-binding domain leucine-rich repeat (NLR)-type immune receptors, leading to NLR-triggered immunity. Some PRRs may also recognize apoplastic PPN effectors and induce PTI. Plant immune responses against PPNs include the secretion of anti-nematode enzymes, the production of anti-nematode compounds, cell wall reinforcement, production of reactive oxygen species and nitric oxide, and hypersensitive response–mediated cell death. In this review, we summarize the recognition mechanisms for PPN infection and what is known about PPN-induced immune responses in plants.

Highlights

Plant-parasitic nematodes (PPNs) are among the most devastating agricultural pests worldwide with an annual global crop loss estimated at about 80 billion USD (Jones et al, 2013)
Exogenous treatment with OGs enhances resistance against Cyst nematode (CN). These results suggest that upon CN infection, Arabidopsis PGIP1 releases OGs, triggering pattern-triggered immunity (PTI) (Shah et al, 2017)
Double mutants cyp79b2/b3 which do not accumulate indolic glucosinolates are more susceptible to CNs (Shah et al, 2017), while pad3, camalexin-deficient mutants are more susceptible to root-knot nematode (RKN) than wild type (Teixeira et al, 2016). These results suggest that some indole glucosinolates including camalexin have some inhibitory effects on PPNs, but there have so far been no reports of direct toxicity of indolic glucosinolates on PPNs

Summary

Introduction

Plant-parasitic nematodes (PPNs) are among the most devastating agricultural pests worldwide with an annual global crop loss estimated at about 80 billion USD (Jones et al, 2013). PPN infections induce host-cell damage, they likely produce DAMP(s), which results in PTI induction.

Results

Conclusion